KR20150104575A - Systems and methods for thermally managing high-temperature processes on temperature sensitive substrates - Google Patents

Abstract

A method for depositing one or more thin film layers on a flexible polyimide substrate having opposing front and rear outer surfaces comprises the steps of: (a) heating the front outer surface of the flexible polyimide substrate to a flexible Heating the flexible polyimide substrate to a temperature higher than the temperature of the rear outer surface of the polyimide substrate; And (b) depositing one or more thin film layers on the front outer surface of the flexible polyimide substrate. The deposition zone for performing the method comprises: (a) one or more physical vapor deposition sources configured to deposit one or more metal materials on a first outer surface of the substrate; And (b) one or more radiation zone boundary heaters.

Description

Field of the Invention [0001] The present invention relates to a system and method for thermally managing a high-temperature process on a temperature-sensitive substrate,

Cross-reference to related application

This application is a continuation-in-part of U.S. Patent Application No. 14 / 150,376, filed January 8, 2014, which claims the benefit of priority to U.S. Provisional Patent Application No. 61 / 750,709, filed January 9, . Each of the foregoing applications is incorporated herein by reference.

Photovoltaic devices generate current in response to incident light. One class of photovoltaic devices commonly used today is based on crystalline silicon solar absorber layers. Crystalline silicon photovoltaic devices include, for example, thick silicon wafers. These wafers are brittle and can not bend without risk of damage, so the wafers must be placed on a rigid substrate such as a large area rigid glass substrate. Although crystalline silicon photovoltaic devices can achieve relatively high efficiencies, they are typically expensive and heavy. In addition, their inflexibility prohibits their use in non-planar applications, or in applications where they are subjected to bending. Also, their weight inhibits some rooftop applications.

Therefore, there is great interest in the development of "thin-film" photovoltaic devices that are potentially thinner, lighter, and less expensive than crystalline silicon photovoltaic devices. In addition, the thin film photovoltaic device will typically withstand at least some degree of warping, which potentially allows the use of a flexible substrate, making the photovoltaic device flexible. Flexible photovoltaic devices can advantageously be used in applications that can follow a non-planar surface and / or are subject to bending warpage.

FIG. 1 shows a cross-sectional view of a conventional thin film photovoltaic device 100 including a thin film stack 102 disposed on a substrate 104. The photovoltaic stack 102 includes a first electrical contact layer 106, such as a molybdenum layer, disposed on the first or front outer surface 108 of the substrate 104. A solar absorbing layer 110 is disposed on the first electrical contact layer 106 and a heterojunction partner layer 112 is disposed on the solar absorbing layer 110. A second electrical contact layer 114, such as a conductive oxide layer, is typically disposed on the heterojunction partner layer 112. The solar absorbing layer 110 and the heterojunction partner layer 112 collectively form a P-N photoconductive junction, which generates a current in response to incident light. The first and second electrical contact layers 106 and 114 provide an electrical interface to the photovoltaic junction. Some examples of possible solar absorber layer materials include selenium-based chalcogenide, such as copper-indium-di-selenide (CIS), or alloys thereof. Some examples of CIS alloys include copper-indium-gallium-di-selenide (CIGS), silver-copper-indium-gallium-di-selenide (AgCIGS), and copper- indium- . It is also of interest in certain applications to replace selenium in solar absorbers with other VI group elements such as sulfur or tellurium or to alloy them. Some examples of possible heterojunction partner layer materials include cadmium sulfide, metal oxides, or alloys thereof. Additional layers such as buffer layers and / or stress relief layers are often added to the photovoltaic device 100. For example, a metal layer, such as a molybdenum layer 118, is sometimes disposed on the rear outer surface 116 of the substrate 104 to provide stress relief and dissipate static electricity.

Many photovoltaic devices include a plurality of photovoltaic cells that are electrically coupled in series and / or in parallel to meet voltage and / or current requirements of a given application. Often, it is desirable that a plurality of photovoltaic cells are monolithically integrated on a common substrate. Monolithic integration enables the customization of device output voltage and output current rating during device design, allowing the device to be tailored to the intended application of the device. In addition, monolithic integration can be achieved by reducing the pitch between adjacent photovoltaic cells as compared to non-monolithically integrated photovoltaic devices, and by reducing the pitch between adjacent photovoltaic cells, By reducing or eliminating the use of bus bars, it promotes small device size and good aesthetic characteristics.

However, monolithic integration requires that the outer surface of the device substrate, such as the outer surface 108 (FIG. 1) of the substrate 104, be a dielectric. Specifically, the surface must be dielectric to allow electrical isolation of adjacent photovoltaic cells by cell isolation scribes, sometimes referred to as "P1" scribes. Instead, if the substrate outer surface is conductive, or if the P1 scribe passes through the surface dielectric to the conductive substrate, adjacent photovoltaic cells will be electrically shorted together, thereby rendering the P1 scribes ineffective. Some examples of monolithic integration techniques, including the use of electrical isolation scribes, are disclosed in Misra, U.S. Patent Application Publication No. 2008/0314439, which is incorporated herein by reference.

The dielectric surface can be obtained on a conductive flexible substrate, such as a metal foil, by applying a dielectric coating to the substrate. However, this procedure may be difficult to implement because the dielectric coating must be free of defects such as pinholes to prevent electrical shorting of the photovoltaic cell. Additionally, dielectric coatings are susceptible to damage during thin film deposition on substrates as well as during monolithic integrated patterning processes.

Alternatively, a dielectric substrate may be used with monolithic integration. However, there are not many flexible substrate materials that are both dielectric and capable of withstanding high temperature processing associated with thin film deposition. One possible flexible dielectric substrate material is flexible glass. However, flexible glass substrates are still in the developmental stage and are not available for use in high volume applications. Another flexible dielectric substrate material is polyimide. Thin polyimide substrates are widely available, and some formulations can withstand treatment temperatures of up to 450 degrees Celsius for a short period of time, often for less than 30 minutes.

Figure 2 illustrates a prior art CIGS deposition configured to form a CIGS solar absorber layer on a flexible polyimide substrate 202 having opposite front and rear outer surfaces 218 and 228 and a thickness 230, Region 200 is shown. The substrate 202 is provided with an electrical contact layer (not shown) on the front outer surface 218, wherein the contact layer is similar to the layer 106 of FIG. A stress relief layer (not shown) similar to layer 118 of FIG. 1 is selectively disposed on the rear outer surface 228. The deposition zone 200 includes a plurality of sources that respectively emit metal plumes 212, 214 and 216 that are subsequently disposed in front of the substrate 202. In this system, the three sources 204, 206, 208 place metal elements on the front outer surface 218 of the substrate 202, which typically include one or more of copper, indium, and gallium . A selenium manifold 220 provides selenium vapor 222 to the deposition zone 200 at the front 210 of the substrate 202. The substrate heaters 224 disposed at the rear 226 of the substrate 202 provide radiant heat to the rear outer surface 228 of the substrate 202. A zone enclosure and a vacuum pump (not shown) maintain a vacuum within the deposition zone 200. Copper, indium, and gallium, which are emitted from the sources 204, 206, 208 onto the front outer surface 218 of the substrate 202 collectively react in the presence of selenium vapor 222, given the proper thermodynamic environment The precursor of the CIGS layer or the entire CIGS layer is formed on the front outer surface 218 of the substrate.

The metal sources 204, 206, 208 provide some heat to the front outer surface 218. In addition, additional heaters (not shown) are sometimes placed in front of the substrate 202 to improve early deposition run stability and prevent elements from condensing and re-evaporating. If present, these additional heaters will also heat the front outer surface 218 somewhat. However, the substrate heaters 224 that heat the rear outer surface 228 of the substrate provide most of the thermal energy needed to enable CIGS deposition. The substrate heaters 224 may require different set points for each other to achieve the required substrate 202 temperature due to the different heating levels provided by the sources 204, 206, 208. As is known in the art, CIS / CIGS deposition requires high substrate temperatures, and photovoltaic efficiency is often dependent on substrate temperature. For example, substrate temperatures in excess of 500 degrees Celsius are typically needed to obtain the highest efficiency CIS / CIGS photovoltaic devices. Additionally, during the co-evaporated CIGS process, Se can be used to reduce the size of the Se vapor clusters, for example by using a Se furnace or a cracker, Studies have shown the potential benefits of increasing thermal energy. (For example, M. Kawamura et al., "Cu (InGa) Se2 thin-film solar cells grown with cracked selenium," Journal of Crystal Growth, vol. 311, January 15, 2009, pp. 753-756 ] Reference). While rigid glass substrates are durable to these temperatures, flexible polyimide substrates deteriorate at elevated temperatures thereby limiting CIS / CIGS deposition processes on polyimide substrates. Additionally, polyimide substrates are highly susceptible to adsorption of water vapor, which may subsequently be released when heated during CIS / CIGS production. If extreme care is not taken to ensure that the polyimide substrates are adequately degassed prior to the deposition of the electrical contact layer, water may be trapped under the first electrical contact layer during substrate heating, cracking and blistering may occur. Cracking and blistering can significantly impair photovoltaic device performance and / or manufacturing yield.

In one embodiment, a method for depositing one or more thin film layers on a flexible polyimide substrate having opposed front and rear outer surfaces comprises the steps of: (a) forming a flexible polyimide substrate having a front outer surface Heating the flexible polyimide substrate such that the temperature of the flexible polyimide substrate is higher than the temperature of the rear outer surface of the flexible polyimide substrate; And (b) depositing one or more thin film layers on the front outer surface of the flexible polyimide substrate.

In one embodiment, a deposition zone for depositing a material on a substrate having a first outer surface of width x depth includes: (a) one or more deposition layers on a first outer surface of the substrate, One or more physical vapor deposition sources configured to deposit metallic materials; And (b) one or more radiant zone boundary heaters. Each radiation zone boundary heater includes an outer heating surface configured to emit infrared radiation and at least one outer heating surface is angularly displaced from the first outer surface of the substrate by an angle of less than 90 degrees. Each outer heating surface is within a line of sight looking at at least a portion of the first outer surface of the substrate.

1 is a sectional view of a conventional thin film photovoltaic device.
Figure 2 shows a prior art CIGS deposition system.
Figure 3 illustrates an example of how heat can be trapped within a polyimide substrate.
Figure 4 illustrates an example of how substrate heating can be minimized by promoting thermal radiation from the rear outer surface of the substrate.
Figure 5 illustrates one CIGS deposition zone, including heaters configured to radiantly heat the front outer surface of the substrate, according to one embodiment.
6 is a cross-sectional view of a photovoltaic device including a layer of CIGS solar absorber formed by the deposition zone of FIG. 5, according to one embodiment.
Figure 7 illustrates a method for depositing one or more thin film layers on a flexible polyimide substrate, according to one embodiment.
Figure 8 illustrates one CIGS deposition zone, including segmented heaters configured to radiantly heat the front outer surface of the substrate, according to another embodiment;

Conventional systems for depositing CIS / CIGS on a polyimide substrate, as discussed above, include a substrate heater configured to radiantly heat the rear outer surface of the substrate while the deposition equipment deposits CIS / CIGS on the front outer surface . Conventional systems employ rear exterior surface heating for two reasons: (1) it has been commonly thought that rear surface heating is required to obtain uniform heating for robust CIS / CIGS deposition, (2) The heating is that the substrate heaters are placed outside the paths of the CIS / CIGS sources.

However, the thermal modeling of the inventors shows that during typical CIS / CIGS deposition, there is a small but insignificant thermal gradient across the thickness of the substrate. For example, the heating applied to the rear outer surface 228 side of the substrate 202 is greater than the thickness 230 of the substrate when the contact layer is disposed on the front outer surface 218 (see FIG. 2) Followed by a small (e. G., 3 to 7 C) thermal gradient. Thus, the front outer surface 218 of the substrate is slightly colder than the rear outer surface 228 under these conditions. This thermal gradient may be more or less noticeable depending on the quality of the contact between the coating and the substrate. It is presumable that the front-to-back temperature gradient is not a problem in conventional glass or metal substrates, and in the latter case there is little or no gradient because the substrate heaters are of high quality CIS / CIGS As desired to achieve sufficient heat on the front outer surface of the substrate. However, in the case of temperature-limited substrates such as polyimide or possibly thin glass, the substrate heaters can not be controlled above the substrate temperature limit, thereby potentially leading to a front outer surface for reacting high quality CIS / CIGS The number of rows is reduced. Thus, in the case of a 5 deg. C thermal gradient across the substrate thickness, applying heat to the front side of the substrate will result in a 10 deg. C lower backside temperature to achieve the same front side temperature as compared to the rear side heating.

The inventors believe that the thermal gradients during CIS / CIGS deposition can be attributed to the combination of the insulating properties of the polyimide substrate, the heat reflective front side metal layer, and process driven active radiation heating and cooling in the vacuum chamber Respectively. 3 illustrates a cross-sectional view of a polyimide substrate 300 that includes a front metal layer 302 on the front outer surface 304 and a rear metal layer 306 on the rear outer surface 308. As shown in FIG. The heat is transferred primarily to the substrate 300 and from the substrate by radiation during the CIS / CIGS deposition because the deposition is done in vacuum.

Consider a scenario in which the rear outer surface 308 is heated by the radiation 310 impinging on the outer surface 322 of the rear side metal layer 306. A portion 312 of radiation 310 is reflected away by the rear side metal layer 306 while a portion 314 of radiation 310 is transmitted through the rear side metal layer 306 and onto the substrate 300 Lt; / RTI > Due to the relatively low thermal conductivity of the substrate 300, the heat is conducted relatively slowly through the substrate 300 so that, despite some incident thermal radiation from the hot source, The back 316 of the substrate 300 is warmer than the front 318 of the substrate. In addition, a portion of the radiation 314 that is not absorbed by the substrate 300 is reflected back into the substrate 300 by the front metal layer 302, as indicated by arrow 320, ) Is further heated. Similarly, when the backside metal is not used, the primary radiation from the rear side heaters and the reflected radiation from the back of the front metal layer 302 result in substrate heating. In any case, the front outer surface 324 is radiatively cooled because its line of sight is that of substantially cold surfaces.

Thus, the inventors determined that when depositing CIS / CIGS on the front outer surface, it is better to heat the front outer surface of the polyimide substrate instead of the rear outer surface thereof. For example, the heating of the front outer surface may potentially cause the heating radiation to be substantially confined to the front side of the substrate where CIS / CIGS deposition takes place, thereby reducing the CIS / CIGS deposition, without excessive heating of the entire substrate as required using conventional techniques. / CIGS reaction. This ability to improve CIS / CIGS reaction while avoiding excessive substrate heating promotes device reliability and high manufacturing yields by reducing substrate degradation. In addition, heating the front outer surface of the substrate can provide sufficient thermal energy to achieve a small Se vapor cluster size during the co-evaporation CIGS deposition process, without requiring the use of Se furnaces or crackers.

The inventors have also found that heating of the polyimide substrate during CIS / CIGS deposition on the front outer surface can be further minimized by promoting radiant emission of heat from the rear outer surface. 4 shows a cross-sectional view of a polyimide substrate 400 having opposed front and rear outer surfaces 402, A front metal layer 406, such as a molybdenum layer, is disposed on the front outer surface 402. It is assumed that the substrate 400 is heated by the radiation 408 impinging on the front metal layer 406. A portion 410 of radiation will flow into the substrate 400 through the front metal layer 406, along with some conducted heat flow. It is desirable to help minimize the substrate heating by preventing the thermal radiation 410 from escaping the rear outer surface 404 and the radiation 410 being trapped within the substrate 400. As discussed above, excessive substrate heating may cause a number of undesirable effects, and thus it is desirable to minimize substrate heating.

With reference to Fig. 4, the rear metal layer reflects heat back into the substrate from the substrate and front metal layer, thereby inhibiting heat radiation in a direction away from the substrate. Such inhibition may be removed by omitting the rear metallic coating, or by using an infrared transparent coating 412 as a stress matching layer instead of a rear metallic coating. Additionally, thermal radiation in a direction away from the substrate can be facilitated by allowing the transmissive coating 412 to become a high emittance coating. In some embodiments, the high emittance coating is a dielectric coating that reduces the risk of unwanted electrical shorting of photovoltaic cells. Some examples of high emittance coatings include transparent oxides such as Al ₂ O ₃ , SiO _x , and light-transparent nitrides. These materials typically have a minimum absorption and a low conductivity to achieve infrared transmission and high emittance.

FIG. 5 illustrates one CIGS deposition zone 500 configured to deposit CIGS on a flexible polyimide substrate 502. The deposition zone 500 has a length 504, a height 506, and a width (not numbered) perpendicular to the length and height directions. The deposition zone 500 includes a vacuum pump 510 and an enclosure 508 that collectively form a vacuum chamber configured to maintain a vacuum inside the enclosure 508. A substrate handling apparatus (not shown) inside and / or outside of the area 500, such as pay-out and take-up spools and substrate support rollers, The substrate 502 is supported within the area 500 so that the front outer surface 512 of the substrate 502 is disposed substantially in the length x width directions. In some embodiments, the substrate handling apparatus may also translate the substrate 502 through the region 500 in the direction of the length 504.

The deposition zone 500 includes a plurality of physical vapor deposition sources configured to deposit metallic materials, in this embodiment three sources 514, 516, 518 are shown. These sources provide, for example, copper, indium, and gallium as well as other elements required to produce the required semiconductor compound in the zone 500. Physical vapor deposition sources 514, 516 and 518 are disposed in front of substrate 502 and include metal platums 522, 524, and 526 that provide at least some of the elements required to produce the required semiconductor compound. 526, respectively. For example, in some embodiments, the physical vapor deposition sources 514, 516, 518 place copper, indium, and gallium on the front outer surface 512 of the substrate 502, respectively. A selenium manifold 528 is typically included to provide the selenium vapor 530 to the deposition zone 500.

The deposition zone 500 further includes one or more radiation zone boundary heaters 532. In the present document, specific examples of articles may be referred to using numbers in parentheses (e.g., heater 532 (1)), while reference numerals without parentheses (e.g., heaters 532) Refers to any such article. Each radiation zone boundary heater 532 has its own outer heating surface 536 configured to emit infrared radiation for radiant heating. The outer heating surface 536 is within the line of sight of at least a portion of the substrate outer surface 512. In some embodiments, the heaters 532 are electric radiant heaters. The radiation zone boundary heaters 532 (1) to 532 (4) are arranged such that their respective heating surfaces 536 are disposed in substantially length x width directions such that the heating surfaces are at least spaced apart from the front outer surface 512 of the substrate Part and a view factor. In the context of the present document, the shape factor of the first surface relative to the second surface is (i) the ratio of the total radiation leaving the first surface to the radiation beam leaving the first surface impinging on the second surface. For example, the shape factor of the heating surface 536 (1) with respect to the outer surface 512 of the substrate may be (i) the infrared radiation band (ii) leaving the surface 536 ) The total infrared radiation leaving the heating surface 536 (1). Radiation zone boundary heaters 532 (5) and 532 (6), on the other hand, are positioned such that their respective heating surfaces 536 are at a respective angle 540 of less than 90 degrees, such as 45 degrees, As shown in Fig. Such an arrangement of the heaters 532 (5), 532 (6) is such that their respective heating surfaces 536 are arranged so that their heating surfaces are not perpendicular to the plane of the outer surface 512 To have a higher, shape factor for the substrate outer surface 512. Placing the heaters so that the heaters have a high form factor with respect to the substrate front outer surface 512 allows direct radiant heating of the front outer surface 512 such that the temperature of the front outer surface 512 is greater than the temperature of the substrate 502 To be higher than the temperature of the rear outer surface 542. The heat from the physical vapor deposition sources 514, 516 and 518 also typically directly heats the front outer surface 512 so that these source and zone boundary heaters 532 collectively provide the necessary thermal energy, Copper, indium, and gallium will react with selenium at the front outer surface 512 to form CIGS.

Additional deposition zones will typically be used with the deposition zone 500 where each additional deposition zone is formed by depositing one or more additional thin film layers on the substrate 502 such that the deposited thin film layers are deposited on the substrate 502, To be formed collectively. For example, the additional deposition zone may be located upstream from the zone 500 to deposit an electrical contact layer on the front outer surface 512 of the substrate before the substrate 502 enters the zone 500 have. As another example, a further deposition zone may be located downstream from zone 500 to deposit a heterojunction partner layer on the CIGS layer deposited in zone 500 such that the CIGS layer and the heterojunction partner layer are deposited on the PN photovoltaic junction Can be collectively formed. In addition, multiple examples of deposition zones 500 may optionally be formed by depositing a plurality of CIGS sublayers on the substrate 502, for example by using the techniques disclosed in U.S. Patent No. 8,021,905 to Nath et al. . In addition, although the deposition zone 500 is shown having its own enclosure 508 and vacuum pump 510, in some alternative embodiments, the zone 500 may include one or more other deposition zones and an enclosure and / Or a vacuum pump.

Figure 6 shows a cross-sectional view of a photovoltaic device 600 that is an example of a photovoltaic device including a CIGS layer formed by a deposition zone 500. [ However, the deposition zone 500 is not limited to form the CIGS layer of the photovoltaic device 600. [ The photovoltaic device 600 includes a first electrical contact layer 602 formed on the front outer surface 512 of the substrate, a CIGS solar absorbing layer (not shown) formed by the deposition zone 500 on the contact layer 602 604, a heterojunction partner layer 606 formed on the solar absorbing layer 604, and a second electrical contact layer 608 formed on the heterojunction partner layer 606. The layers 602, 604, 606, 608 collectively form a thin film stack 610 on the front outer surface 512. The solar absorbing layer 604 and the heterojunction partner layer 606 collectively form a P-N junction, which produces electron-hole pairs in response to incident light. The photovoltaic element 600 may optionally be formed on the rear outer surface 542 of the substrate to facilitate the radiation of heat from the rear outer surface 542 when forming one or more layers of the stack 610. [ Lt; RTI ID = 0.0 > 612 < / RTI > Additional layers such as a buffer layer and / or a stress relief layer may be added to the photovoltaic device 600 without departing from the category of the photovoltaic device.

Although the deposition zone 500 is shown as being configured to deposit CIGS on the substrate 502, the zone 500 may be a CIS, a CIS, another alloy of CIS, or even a temperature limited substrate RTI ID = 0.0 > CIS / CIGS < / RTI > Additionally, although the deposition zone 500 is shown as being configured to directly radiate heat only the front outer surface 512 of the substrate, the zone 500 may be configured to radiate the rear outer surface 542 of the substrate 502 to a radiant heating It should be appreciated that the heaters configured to be further modified to include at the rear 544 of the substrate 502. However, if rear surface heaters are employed, the deposition zone 500 may be used to directly radiantly heat the front outer surface 512, such as zone boundary heaters 532 and physical vapor deposition sources 514, 516, Radiation heat generating elements should be configured to provide most of the thermal energy needed for the CIS / CIGS reaction on the substrate 502 to realize the advantages associated with the front outer surface heating discussed above. In an alternate embodiment, to enhance the radiant heat transfer from the rear outer surface 542 of the substrate, the substrate 502 may be protected from excessive heat accumulation while allowing for a larger front outer surface 512 temperature, 500 further includes a substrate cooler (not shown) disposed at the rear 544 of the substrate 502.

FIG. 7 illustrates a method 700 for depositing one or more thin film layers on a flexible polyimide substrate comprising opposed front and rear outer surfaces. The method 700 begins with heating 702 the front outer surface of the substrate such that the temperature of the front outer surface is higher than the temperature of the rear outer surface. An example of step 702 is to heat the front outer surface 512 of the substrate 502 using zone boundary heaters 532 such that the front outer surface 512 is at a higher temperature than the rear outer surface 542 5). At step 704, one or more thin film layers are deposited on the front outer surface 512. One example of step 704 is to remove the selenium from the sources 514, 516, 518 in the presence of selenium from the elevated temperature manifold 528 to form the CIGS layer 604 on the front outer surface 512 To form a CIGS layer 604 on the front outer surface 512 of the substrate 502 by reacting copper, indium, and gallium, respectively, of the substrate 502 (Figures 5 and 6). Although steps 702 and 704 are shown as separate steps, it is expected that at least some of these steps will be performed simultaneously in many embodiments.

FIG. 8 shows another CIGS deposition zone 800 configured to deposit CIGS on a flexible polyimide substrate 502 in a manner similar to that shown in FIG. The deposition zone 800 is similar to the deposition zone 500 of FIG. 5, but some zone boundary heaters 532 have been replaced with segmented zone boundary heaters 802. The segmented zone boundary heaters 802 are arranged in a manner that allows uniform heating while increasing the form factor towards the substrate 502 so that thermal energy is applied to the heaters 802 while minimizing the effect on the zone length 504. [ Lt; RTI ID = 0.0 > substrate. ≪ / RTI > To accommodate the selenium vapor 530 and / or other deposition elements within the zone 800, the shields 804 are selectively disposed within the spaces between adjacent heaters 802. Shields 804 are optionally fabricated to receive electrical and / or light pass-throughs to receive non-contact means for monitoring CIGS deposition within zone 800. Each zone boundary heater 802 has its own outer heating surface 806 configured to emit infrared radiation for radiant heating. Heaters 802 are positioned so that each outer heating surface 806 is within the line of sight of at least a portion of the outer surface 512 of the substrate. Each heater 802 is disposed such that its outer heating surface 806 is angularly displaced from the front outer surface 512 of the substrate by a respective angle 808 less than 90 degrees, such as 45 degrees. Such an arrangement of the heaters 802 is such that their respective heating surfaces 806 are located on the substrate outer surface 512 higher than those obtained when the heaters are arranged with the heating surfaces perpendicular to the outer surface 512 To have a shape factor for. Some examples of shields 804, outer heating surfaces 806 and angles 808 are labeled in FIG. 8 to enhance exemplary clarity.

Although the systems and methods disclosed herein have been described in connection with CIS / CIGS deposition, they are also suitable for high temperature deposition of other materials, such as high temperature deposition of high-speed crystalline thin film transistors for flexible displays and / Can be applied. Additionally, the systems and methods disclosed herein are not limited to use with polyimide substrates, or even with polymers with additives and fillers, but with thin flexible glass and possibly with insulated metal foils It is also applicable to other temperature sensitive substrates having the same low thermal conductivity. While these substrates may have higher temperature constraints than polyimide, they may exhibit a combination of structural integrity and sensitivity to temperature, which may also benefit from the disclosed systems and methods.

A combination of features

The features described above as well as those claimed below may be combined in various ways without departing from the scope thereof. The following examples illustrate some possible combinations:

(A1) a method for depositing one or more thin film layers on a flexible polyimide substrate having opposing front and rear outer surfaces may comprise the steps of: (a) providing a flexible polyimide substrate having a front outer surface Heating the flexible polyimide substrate such that the temperature of the flexible polyimide substrate is higher than the temperature of the rear outer surface of the flexible polyimide substrate; And (b) depositing one or more thin film layers on the front outer surface of the flexible polyimide substrate.

(A2) In the method described as (A1), the step of heating may comprise radiatively heating the front outer surface of the flexible polyimide substrate using one or more radiant heat generating elements, wherein each of the one or more radiant heat generating elements Is at least partially within the line of sight of the front outer surface of the flexible polyimide substrate.

(A3) In the method described as (A2), the one or more radiant heat generating elements may comprise electroluminescent heaters.

(A4) Any of the methods described as (A1) to (A3) may further comprise maintaining a vacuum around the flexible polyimide substrate during the heating and deposition steps.

(A5) In any of the methods described as (A1) to (A4), the depositing comprises depositing copper-indium-di-selenide and copper-indium-di-selenide on the front outer surface of the flexible polyimide substrate ≪ / RTI > of a material selected from the group consisting < RTI ID = 0.0 > of: < / RTI >

(A6) In any of the methods described as (A1) to (A5), the depositing step may comprise reacting at least copper and / or indium in the presence of selenium.

(A7) Any of the methods described as (A1) to (A6) may further comprise depositing an oxide layer on the back outer surface of the flexible polyimide substrate.

(B1) A deposition zone for depositing a material on a substrate having a first lateral surface of length x length may comprise: (a) a first outer surface of the substrate, the first outer surface of which is configured to deposit one or more metal materials One or more physical vapor deposition sources; And (b) one or more radiation zone boundary heaters. Each radiation zone boundary heater may include an outer heating surface configured to emit infrared radiation and at least one outer heating surface may be angularly displaced from the first outer surface of the substrate by an angle of less than 90 degrees . Each outer heating surface may be in the line of sight looking at at least a portion of the first outer surface of the substrate.

(B2) In the deposition zone described as (B1), at least one of the one or more radiation zone boundary heaters may comprise an outer heating surface arranged in length and width directions.

(B3) In any one of the deposition zones described as (B1) or (B2), the one or more radiation zone boundary heaters may comprise an electric radiant heater.

(B4) Any of the deposition zones described as (B1) to (B3) may further comprise a vacuum pump and enclosure configured to maintain a vacuum within the deposition zone.

(B5) In any of the deposition zones described above as (B1) to (B4), the at least one physical vapor deposition sources comprise at least one layer selected from the group consisting of copper, gallium and indium on the first outer surface of the substrate May be configured to deposit material.

(B6) Any of the deposition zones described as (B1) to (B5) may further comprise a selenium manifold configured to provide selenium vapor to the deposition zone.

(B7) In any of the deposition zones described in (B1) to (B6), one or more physical vapor deposition sources may be configured to deposit at least copper, gallium, and indium on the first outer surface of the substrate have.

(B8) In any of the deposition zones described as (B1) to (B7), the one or more radiation zone boundary heaters may comprise a plurality of radiant heaters separated from each other.

(B9) In the deposition zone described as (B8), the plurality of radiant heaters separated from each other may include first and second radiant heaters, and the deposition zone may be a shielding zone between the first radiant heater and the second radiant heater And the shield is configured to receive one or more deposition elements within the deposition zone.

(B10) In any of the deposition zones described as (B1) to (B7), the one or more radiant zone boundary heaters may be a single radiant heater.

Changes may be made in the method and system without departing from the scope. It is therefore to be understood that the description contained in the above description and shown in the accompanying drawings is to be interpreted as illustrative rather than in a limiting sense. The following claims are intended to cover all references to the scope of the methods and systems which may be referred to by their language as well as the generic and specific features set forth herein.

Claims (17)

1. A method for depositing one or more thin film layers on a flexible polyimide substrate having opposing front and rear outer surfaces,
Heating the flexible polyimide substrate such that the temperature of the front outer surface of the flexible polyimide substrate is higher than the temperature of the rear outer surface of the flexible polyimide substrate; And
And depositing the one or more thin film layers on the front outer surface of the flexible polyimide substrate. 2. The method of claim 1, wherein the heating comprises radiatively heating the front outer surface of the flexible polyimide substrate using one or more radiant heat generating elements, wherein each of the one or more radiant heat generating elements is at least partially Wherein the flexible polyimide substrate is within a line of sight of the front outer surface of the flexible polyimide substrate. 3. The method of claim 2, wherein the one or more radiant heat generating elements comprise electrically radiant heaters. 4. The method of claim 3, further comprising maintaining a vacuum around the flexible polyimide substrate during the heating and depositing steps. 5. The method of claim 4, wherein the depositing comprises depositing a material selected from the group consisting of copper-indium-di-selenide and copper-indium-di-selenide alloys on the front outer surface of the flexible polyimide substrate ≪ / RTI > 6. The method of claim 5, wherein said depositing comprises reacting at least copper and indium in the presence of selenium. 7. The method of claim 6, further comprising depositing an oxide layer on the back outer surface of the flexible polyimide substrate. A deposition zone for depositing material on a substrate having a first outer surface of width x depth,
One or more physical vapor deposition sources configured to deposit one or more metal materials on the first outer surface of the substrate; And
Wherein each radiant zone boundary heater includes an outer heating surface configured to emit infrared radiation and wherein at least one outer heating surface has an angle of less than 90 degrees Wherein each of the outer heating surfaces is within a line of sight looking at at least a portion of the first outer surface of the substrate. 9. The deposition zone of claim 8, wherein at least one of the one or more radiation zone boundary heaters comprises an outer heating surface disposed in length and width directions. 9. The deposition zone of claim 8, wherein the at least one radiation zone boundary heaters comprise an electric radiant heater. The deposition zone of claim 8, further comprising a vacuum pump and an enclosure configured to maintain a vacuum within the deposition zone. 9. The deposition zone of claim 8, wherein the at least one physical vapor deposition sources are configured to deposit at least one material selected from the group consisting of copper, gallium, and indium on the first outer surface of the substrate. 13. The deposition zone of claim 12, further comprising a selenium manifold configured to provide selenium vapor to the deposition zone. 14. The deposition zone of claim 13, wherein the at least one physical vapor deposition sources are configured to deposit at least copper, gallium, and indium on the first outer surface of the substrate. 9. The deposition zone of claim 8, wherein the at least one radiation zone boundary heaters comprise a plurality of radiation heaters separated from each other. 16. The apparatus of claim 15, wherein the plurality of radiant heaters separated from each other include first and second radiant heaters, wherein the deposition zone further comprises a shield disposed between the first radiant heater and the second radiant heater And wherein the shield is configured to receive one or more deposition elements within the deposition zone. 9. The deposition zone of claim 8, wherein the at least one radiation zone boundary heaters are single radiation heaters.

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